#include<stdio.h>#include<sys/types.h>#include<sys/stat.h>#include<fcntl.h> int  main(){		int testdev;	int i;	char buf[100];	char buf1[100]="The content you just written in it!!!";	char buf2[200];	if((testdev=open("/dev/mychardrv",O_RDWR))==-1)	{			printf("！！！打開該設(shè)備文件操作失敗！！！\n");		exit(0);	}	printf("\n###******************Function Read Test**********************###\n");	read(testdev,buf2,200);	printf("######Content  Of   The  Device######\n");	printf("%s\n",buf2);	printf("######Content  Just  Read#####\n");	lseek(testdev,164,0);	read(testdev,buf,40);	printf("%s\n",buf);	printf("\n###******************Function Write Test**********************###\n");	lseek(testdev,41,0);   	write(testdev,buf1,40);	lseek(testdev,41,0);	read(testdev,buf,40);	printf("%s\n",buf);	close(testdev);	return  0;}